In this thesis, we proposed general forms of eigen-mode analysis for multilayer optical waveguides. This study discussed the periodic structure in transverse direction and used the slowly varying envelope approximation to approximate the wave function. Firstly, we presented a general method for analyzing the multilayer nonlinear optical waveguide structure by using modal theory. The nonlinear optical waveguide is a medium whose refractive index changes with the electric field intensity. The general method can also be degenerated into some other special cases for analyzing multilayer nonlinear optical waveguide. Secondly, a general method for analyzing the multilayer optical waveguides with photonic metamaterials characterized by simultaneously negative dielectric permittivity and magnetic permeability was studied. The research pointed out explicitly that the three-layer planar waveguide with photonic metamaterials could support forbidden regions. The complete set of modes of all possible solutions for the TE wave in photonic metamaterials optical waveguide was found. The transverse electric field distributions and dispersion relations in multilayer optical waveguides can be obtained by using these general forms. Finally, we used the general forms to design an all-optical mode converter which composed of a pair of multibranch optical waveguides. The analytical and numerical results show excellent agreement.

With a rapid increase in information capacity of Internet access, high-speed, highly-efficiency, and cost-effectiveness laser source for optical fiber communication is required. High-speed 25Gb/s directly modulated laser is essential of this communication range, because of its simple structure, direct-modulation characteristics, low cost, and integration capability for wavelength division multiplexing (WDM) system, and moreover, it can achieved 100Gb/s data transmission by four channel module system. In this work, data modulation speed of 25Gb/s direct modulation DFB laser has been achieved. By employing high-speed coplanar waveguide structure with semi-insulating substrate, high-speed with f3dB > 20GHz has been demonstrated. By the electrical reflection measurement, it confirmed that the high-speed direction modulation can be realized through reduction of electrical parasitics. The laser chips is measured under continuous-wave mode at room temperature. In 1300nm and 1550nm wavelength device, slope efficiency obtained by taper fiber coupled of 0.045 and 0.07mW/mA respectively, output power up to 2.73 and 3.96mW/facet at 60mA. The Side Mode Suppression Ratio was greater than 35dB. 3dB bandwidth of greater than 16GHz and 20.5GHz, relaxation oscillation frequency of 12GHz and 16.6GHz. Finally, clearly back-to-back 25Gb/s eye diagram and error-floor-free performance were obtained.

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Utilizing the semiconductor processing technology, a large number of optical components can be integrated into a small area. It is of low cost and high reliability and can be massively produced. The PLC(planar light circuit) has become an important component with the opto-communication industry.In this thesis, we aim to study dielectric waveguide termination witha slightly tilted facet. A waveguide with normal termination in the air will have non-zero reflection coefficients due to the impedance difference at the core-air junction. To reduce the reflection of the fundamental mode, it is custom to terminate the waveguide with a small tilted angle. The angle is optimally chosen to avoid spurious scattering into high-order radiation modes.To analyze this problem, we employ the modal expansion method for both the reflected waves and the transmitted waves. We then analytically extend the waves and join the two fields on the bordering line by matching the fields and their normal derivatives. An incomplete transverse-mode integral equation (TMIE) is derived for the reflection and transmission coefficients. The incomplete TMIE is good for waveguide termination with small tilted angles. Our analysis show that for multi-mode 1-D slab waveguide (simulating the 1-D optical fiber), the fundamental mode reflection coefficient is about -28dB down. It gradually reduces to -60dB as we increase the tilt angle from around 8 degrees. The result agrees well with those calculate from frequency-domain finite-difference method.

We investigate the properties of integrated dielectric filters for the purposes of on-chip routing of photons. We started with the use of high quality factor tunable photonic crystal nanobeam cavities and moving on to examine a new class of reflection based reverse designed filters that maintain the footprint of a waveguide while allowing for arbitrary amplitude and phase response. / Engineering and Applied Sciences

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Semiconductor quantum dots are promising candidates as bright, indistinguishable, single-photon sources---making them desirable for applications in quantum computing and quantum cryptography protocols. By embedding the quantum dots in III-V nanowires, the collection efficiency from the quantum dot is greatly increased. Our goal is to develop a platform that allows for the stable and efficient generation of single-photons on chip. This on-chip design offers an enhanced degree of stability and miniaturization, important in many applications involving the processing of quantum information. In this thesis, we demonstrate the efficient coupling of quantum light generated in a III-V photonic nanowire to a silicon-based photonic integrated circuit. We use high quality SiN waveguide devices fabricated by a foundry (LIGENTEC) to minimize coupling and propagation losses through the waveguide. A hybrid integration of these single-photon sources with a photonic integrated circuit is developed by employing a "pick & place" method which uses a nanomanipulator in a scanning electron microscope setup. By tailoring the nanowire geometry, we are able to maximize the efficient coupling between the optical mode of the photonic nanowire and an accompanying SiN waveguide through evanescent coupling. To determine the effectiveness of our integration method, we compare our hybrid devices with free-standing nanowires on their growth substrate. For each set, we measured the optical properties (brightness, spectral purity, lifetime, and single-photon purity) and efficiencies of the devices. We have shown that using tapered nanowires with embedded quantum dots coupled to on-chip photonic structures is a viable route for the fabrication of stable, high-efficiency, single-photon sources. Although the measured collection efficiencies from device to device were substantially different 9.6%~93%, we have found that the optical properties of the hybrid devices were hardly impacted from the transfer process. In fact, from the same nanowire that achieved 93% coupling efficiency, we were able to measure a single photon purity of 97%. By comparing the amount of emitted light collected from both ends of the nanowire (taper and base), we confirmed that the coupling efficiency of the devices have a strong dependence on the geometry of the nanowire as collection from the taper yielded count rates at least 10x greater than from the base. From our promising results, we can envision integrating the nanowire devices with different types of photonic structures such as ring resonators.

The speed and simplicity of the metal-semiconductor-metal (MSM) detector has made it a prime candidate for use in integrated optoelectronic circuits. While in most applications the optical input is coupled in through the top surface of the device, it is also possible to distribute the optical signal by means of transparent waveguides that are located below the absorbing detector layer. By controlling the degree of coupling between the waveguide and detector layers the detectors can be made to act as optical taps. The optical signal can thus be shared among a series of detectors as required in optoelectronic switching applications. We have made a series of simple ridge waveguides, each with a number of MSM structures designed for the characterization of absorption, responsivity and frequency response. A 4x4 optoelectronic switch was also fabricated and analyzed. We show that balancing the switch is accomplished by tailoring the absorption coefficient in the detector region so that all detectors absorb equal amounts of optical power. / Thesis / Master of Engineering (ME)

The speed and simplicity of the metal-semiconductor-metal (MSM) detector has made it a prime candidate for use in integrated optoelectronic circuits. While in most applications the optical input is coupled in through the top surface of the device, it is also possible to distribute the optical signal by means of transparent waveguides that are located below the absorbing detector layer. By controlling the degree of coupling between the waveguide and detector layers the detectors can be made to act as optical taps. The optical signal can thus be shared among a series of detectors as required in optoelectronic switching applications. We have made a series of simple ridge waveguides, each with a number of MSM structures designed for the characterization of absorption, responsivity and frequency response. A 4x4 optoelectronic switch was also fabricated and analyzed. We show that balancing the switch is accomplished by tailoring the absorption coefficient in the detector region so that all detectors absorb equal amounts of optical power. / Thesis / Master of Engineering (ME)